1. Field of the Invention
The present invention relates to a radio control transmitter for a model and a method for transmission and reception of a signal by this radio control transmitter.
2. Description of the Related Art
An object to be controlled (hereafter referred to as “radio-controlled object) such as a radio control model, and in particular, model air vehicles such as a model airplane and a model helicopter, requires much skill to control its diverse and complex maneuvering, and various radio control transmitters are known that have trainer features so that a beginner can practice without unfortunately letting the air vehicle crush and burn.
As shown in FIG. 10, the trainer features involves two radio control transmitters that are connected to each other via a trainer cable 11, the trainer cable supporting the trainer features to enable a trainer mode.
When the trainer mode is enabled, one of the two interconnected radio control transmitters serves as an instructor's device (i.e., an instructor's radio control transmitter 1A), and the other thereof as a trainee's device (i.e., a trainee's radio control transmitter 1B).
By way of example, the one that has been turned on first may automatically serve as the instructor's radio control transmitter 1A. In this case, the other radio control transmitter may be automatically turned on in response to turning on of the one radio control transmitter serving as the instructor's radio control transmitter 1A to serve as the trainee's radio control transmitter 1B.
When a trainee attempts maneuvering operation for the trainee's radio control transmitter 1B that has been placed in the trainer mode, the trainee's radio control transmitter 1B converts the maneuvering data corresponding to the maneuvering operation into a trainer signal in accordance with a predetermined signal specification, and transmits the trainer signal via the trainer cable 11 to the instructor's radio control transmitter 1A.
The radio control transmitter supporting the trainer features may have a trainer switch. In response to the operation of the trainer switch, the instructor's radio control transmitter 1A can switch between an active mode and a passive mode.
In the passive mode, the maneuvering data in the form of the trainer signal input by the trainee's radio control transmitter 1B is transmitted as the maneuvering signal via an antenna 7 to the radio-controlled object 10. In the passive mode, the radio-controlled object 10 operates in response to the maneuvering operation for the trainee's radio control transmitter 1B.
In contrast, in the active mode, the maneuvering data corresponding to the maneuvering operation for the instructor's radio control transmitter 1A is transmitted as the maneuvering signal to the radio-controlled object 10. This means that the maneuvering data corresponding to the trainer signal by the trainee's radio control transmitter 1B is not transmitted as the maneuvering signal to the radio-controlled object 10.
For example, when the trainee is to practice, an instructor places the radio control transmitter 1A in the passive mode. In the passive mode, the maneuvering signal corresponding to the maneuvering operation made by the trainee using the trainee's radio control transmitter 1B is transmitted to the radio-controlled object 10. Thus, the trainee is allowed to operate the radio-controlled object 10.
However, suppose that the trainee erroneously attempts an operation in the passive mode, making a flight condition of the radio-controlled object unstable, or suppose that a situation necessitates a maneuvering operation that requires skill, which may be a landing operation when the radio-controlled object is an air vehicle.
In such situations, the instructor operates the trainer switch to exit the passive mode and enter the active mode so that, even when the trainee operates the trainee's radio control transmitter 1B, the radio-controlled object 10 does not operate in response to the trainee's maneuvering operation, and instead, it only operates in response to the maneuvering operation by the instructor's radio control transmitter 1A. With the active mode entered, the instructor may attempt maneuvering operation for recovering the radio-controlled object from the unstable flight condition or the landing operation.
In this manner, by virtue of the trainer mode and with the help of the instructor always available, the trainee can practice maneuvering operation safely without crushing the radio-controlled object to the ground or failing in the landing operation.
FIG. 11 illustrates a known system configuration supporting the trainer features.
In the known system shown in FIG. 11, the instructor's radio control transmitter 1A includes a trainer signal receiver 12. The trainer signal receiver 12 is a receiver dedicated to reception of the radio-transmitted trainer signal. The trainer signal receiver 12 is separate from the radio control transmitter as such and is connected to the instructor's radio control transmitter 1A.
In the known system of FIG. 11, when the trainer mode is entered, one of the two devices to which the trainer signal receiver 12 is connected serves as the instructor's radio control transmitter 1A, and the other thereof to which the trainer signal receiver 12 is not connected serves as the trainee's radio control transmitter 1B. Also, the connection between the trainer signal receiver 12 and the instructor's radio control transmitter 1A may be wired connection using a cable.
Further, in the known system configuration of FIG. 11, the trainee's radio control transmitter 1B is configured to emit a radiowave carrying the trainer signal corresponding to the maneuvering operation via the antenna 7. The trainer signal that has thus been emitted is received by the trainer signal receiver 12 and then input to the instructor's radio control transmitter 1A.
Also in the known system of FIG. 11, the instructor's radio control transmitter 1A switches between the passive mode and the active mode by operation of the trainer switch. The instructor's radio control transmitter 1A functioning in the passive mode emits a maneuvering signal carrying the maneuvering data contained in the input trainer signal via the antenna 7 and transmits it to the radio-controlled object 10.
In the active mode, the instructor's radio control transmitter 1A mode transmits a maneuvering signal carrying a maneuvering data obtained corresponding to a maneuvering operation of the instructor's radio control transmitter 1A, in place of the maneuvering data carried by the trainer signal.
FIG. 12 illustrates an exemplary case where the maneuvering signal or the trainer signal is a PPM (Pulse Position Modulation) signal.
In the maneuvering signal or trainer signal, channels may be assigned on a per-control-target (function) basis, the control targets including aileron and elevator. This may be called a “channel order.” The maneuvering signal or the trainer signal illustrated in FIG. 12 includes a maximum of four (4) channels CH1 to CH4.
In the maneuvering signal or trainer signal in the form of the PPM signal, a reset pulse Prs rises at the beginning of one cycle. A channel pulse Pch1 corresponding to the channel CH1 rises after a lapse of a predetermined period of time following the rising edge of the reset pulse Prs, i.e., after a lapse of a reset period Trs. In other words, when the first pulse (i.e., the reset pulse Prs) rose, the reset period Trs elapsed, and the next pulse rose following the first pulse, then the next pulse is identified as the channel pulse Pch1.
Following the rising edge of the channel pulse Pch1, a channel pulse Pch2 corresponding to the next channel CH2 rises in response to lapse of a predetermined time T1, Thereafter in a similar manner, a channel pulse Pch3 corresponding to the channel CH3 and a channel pulse Pch4 corresponding to the channel CH4 rise after a lapse of predetermined times T2 and T3, respectively. Further, a next cycle's reset pulse Prs will rise after a lapse of a predetermined time T4 following a rising edge of the channel pulse Pch4.
The one cycle for the PPM signal as the maneuvering signal or the trainer signal is about 20 msec, depending upon the number of channels.
The times T1 to T4 in the above PPM signal are also referred to as pulse intervals. The pulse intervals T1 to T4 are each defined for corresponding each of the channel pulses Pch1 to Pch4. The pulse intervals T1 to T4 each indicate an amount of control for corresponding each of the functions assigned to the channels CH1 to CH4, respectively. A time length of the pulse intervals T1 to T4 between adjacent two of the series of channel pulses in the PPM signal represents the maneuvering data for the corresponding channel.
A known radio control transmitter of this kind is, for example, disclosed in Japanese Patent Application Laid-Open Publication No. H07-31751.
Referring again to FIG. 10, the instructor's radio control transmitter 1A and the trainee's radio control transmitter 1B are physically connected to each other via the trainer cable 11. For this reason, both of the operator acting as the instructor and the operator acting as the trainee have constraints regarding mutual positional relationship and postures, which make it difficult to maneuver the radio-controlled object.
In contrast, the configuration shown in FIG. 11 is not affected by the above constraints, for the trainer signal is transmitted and received via radio waves. However, the trainer signal receiver 12 in the configuration shown in FIG. 11 is a separate device operating independently from the radio control transmitter 1A. Furthermore, since the radio control transmitters can take various dimensions, the trainer signal receiver 12 in actual situation is often connected to the instructor's radio control transmitter 1A while hanging therefrom. Such a state may, in addition to the poor unsophisticated appearance, cause difficulty in maneuvering operation.
Also, in both of the configurations of FIGS. 10 and 11, it is cumbersome to provide components and/or devices other than the radio control transmitters as such, i.e., the trainer cable 11 in the case of FIG. 10 or the trainer signal receiver 12 in the case of FIG. 11.